1. Field of the Invention
The present invention relates to a steam system that reduces power consumption by driving a compressor and the like using steam.
The present application claims priority based on Japanese Patent Application No. 2008-055686 filed in Japan on Mar. 6, 2008 and Japanese Patent Application No. 2008-212381 filed in Japan on Aug. 21, 2008, the contents of which are hereby incorporated by reference.
2. Description of the Related Art
Japanese Unexamined Patent Publication No. 63-45403 (Claims, FIG. 1, and P.2, lower left column, lines 1 to 5 of publication) discloses a method of holding the back pressure of the steam on the steam flow-out side constant regardless of the load fluctuation by driving an air compressor (2) with a screw-type expander (1), and controlling the steam that flows into the screw-type expander (1) with an adjustable valve (10) at the time of load fluctuation of the air compressor (2) and controlling a by-pass valve (9) arranged between the steam flow-in side and the steam flow-out side of the screw-type expander (1). The by-pass valve (9) is controlled by detecting the back pressure of a steam outlet tube (5) from the screw-type expander (1) with a detector (20). The adjustable valve (10) is controlled by detecting number of rotations of a drive shaft of the screw-type expander (1) with a detector (23).
Japanese Unexamined Patent Publication No. 9-68006 (claims 1, 6, 8, paragraphs [0019], [0021], [0024], and FIG. 1) discloses a gas turbine facility including a gas turbine (1), a power generator (8) driven by the gas turbine (1), an exhaust heat boiler (13) that uses the exhaust gas of the gas turbine (1) as a heat source, a screw-type steam engine (30) that uses the steam supplied from the exhaust heat boiler (13) as a power source, and a fuel compressor (11), driven by the steam engine (30), for compressing fuel and supplying the same to a combustor (3) of the gas turbine (1). In such a gas turbine facility, the fuel supply amount from the fuel compressor (11) to the gas turbine (1) is adjusted by a by-pass control valve (37) arranged between an inlet and an outlet of the fuel compressor (11), but the steam amount to be supplied to the steam engine (30) is adjusted by a control valve (32) with respect to a large load fluctuation that cannot be fully controlled with the by-pass control valve (37). The fuel compressor (11) is driven by a motor (10) at the time of startup of the exhaust heat boiler (13) or at the time of steam engine (30) failure.
Japanese Unexamined Patent Publication No. 4-353201 (paragraphs [0022] to [0028], and FIG. 1) discloses a device in which a steam turbine (9) is connected on an input side of a screw rotor of a compressor (1) by way of an electric motor (7) and a clutch (8), where the power by the steam turbine (9) is added to the power by the motor (7) to drive the screw rotor at the time of the operation of the steam turbine (9). In such a device, the steam turbine (9) is switched between drive and stop by the opening and closing of a steam valve (10). Focusing on the fact that a shaft power of the compressor (1) is dominated by an intake side pressure and a discharge side pressure, the steam valve (10) is opened to operate the steam turbine (9) when the shaft power of the compressor (1) is within a tolerable power range based on a low-pressure pressure detector (18) for detecting the intake side pressure of the compressor (1) and a high-pressure pressure detector (19) for detecting the discharge side pressure. The compressor (1) has the slide valve thereof controlled by a capacity control device (14) so as to be capacity controlled.